The properties of hydroxyapatite ceramic coatings produced by plasma electrolytic oxidation by Adeleke, Sakiru Adekunle, Ramesh, Singh, Bushroa, Abdul Razak, Ching, Yern Chee, Sopyan, Iis, Maleque, Md Abdul, Krishnasamy, Sivakumar, Chandran, Hari, Misran, Halina, Sutharsini, Ubenthiran